20847639397 has 12 divisors (see below), whose sum is σ = 22581127620. Its totient is φ = 19238464128.

The previous prime is 20847639353. The next prime is 20847639413. The reversal of 20847639397 is 79393674802.

It can be written as a sum of positive squares in 6 ways, for example, as 7205632996 + 13642006401 = 84886^2 + 116799^2 .

It is not a de Polignac number, because 20847639397 - 2⁷ = 20847639269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20847639347) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 648303 + ... + 679699.

It is an arithmetic number, because the mean of its divisors is an integer number (1881760635).

Almost surely, 2^20847639397 is an apocalyptic number.

It is an amenable number.

20847639397 is a deficient number, since it is larger than the sum of its proper divisors (1733488223).

20847639397 is a wasteful number, since it uses less digits than its factorization.

20847639397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35352 (or 35339 counting only the distinct ones).

The product of its (nonzero) digits is 13716864, while the sum is 58.

The spelling of 20847639397 in words is "twenty billion, eight hundred forty-seven million, six hundred thirty-nine thousand, three hundred ninety-seven".